CSW wrote:

I got the numbers on the 2015 spark showing the lower range estimate today:

After a 50 mile trip, shows 63% used and used 10.4kwh (53% driving and 10% climate control) = so 16.50kwh useable battery??

Isn't that low?

Keep in mind that there is some imprecision in the calculation as the percentage only increments in full % and the kWh in .1 kWh

So you can have up to .9% error on the driving % and .09 error on the kWh, if they cumulate, it can make the calculation of the capacity vary by almost 1 kWh.

To minimize imprecision error, watch the % number and the kWh number, and try to note them when they both change almost at the same time (do keep an eye on the road

)

Also make sure you are adding all non zero percentages (driving, conditioning and climate), but if possible make measurement when conditioning and climate are at zero, as each of them carries its own imprecision, so if you have to add more than one percentage, the imprecision goes up.

Accounting for the imprecision of the measures, what you found both on the usable capacity and the usage explains the difference of range you mentioned in your first post.

To recap 2016 over 2015

87 over 67 +29%

4.6 m/kwh over 4.1 m/kwh is +12%

17.8 kwh over 16.5 kwh is + 8%

Range based on above number would be 4.6 x 17.8 = 82 miles over 4.1 x 16.5 = 67.65 miles

You can fine tune your estimated usable capacity with more measures following info given above and in other posts.

But between a bit less capacity and a more aggressive driving, your estimated range difference makes sense.